Two-speed engine governor



Dec. 23, 1952 A. w. RICKENBACHY 2,576

TWO-SPEED ENGINE GOVERNOR Filed Nov. 1, 1950 INVENTOR. AUGUST M.RIG/(ENBACH ZQMQ ATTORNEY.

Patented Dec. 23, 1952 UNITED rates ears T QEFICE T'WO-SPEED ENGINEGOVERNOR 7 Claims.

The present invention relates to governors and has particular referenceto a mechanism for use with a fly ball governor which is arranged tocontrol the operation of an associated engine at either of twopredetermined operating speeds.

Although it may be used with purely mechanical loads, such as pumps, theherein disclosed govrnor mechanism has particular utility when used inconjunction with a stand-by electric power plant, especially anengine-generator set which must be operated for protracted periodsduring which energy may be drawn at varying rates from the generator. Inapplications of this type an engine-generator set frequently mustoperate at constant speed and a fly ball governor is often provided tohold the speed constant regardless of the load which is imposed. Sincethe set must be capable of producing full load output, the constantspeed of operation for which the governor must be adjusted must be closeto the full load speed of the engine with the result that the set mayoperate for long time periods at full load speed but with a very smallpower output due to the small load on the generator during theseperiods'. This condition may foster rapid wear of the engine which ishighly undesirable since the life span of the engine may be reduceddespite the fact that the set is often operated considerably below fullload output.

It is, therefore, an object of the present invention to provide for useon engine-generator sets a two-speed governor which is designed toregulate the engine speed so that full load power may be produced duringperiods of large demand but the engine speed may be reduced to a lowspeed or idling level during periods when reduced loads or no load isimposed on the generator.

Since the power consumption of engine accessories, associated coolingfans, and related transmission units decreases as the engine speeddecreases, overall operating efiiciency can be improved by restrictinglow load operation to low speeds. The herein disclosed governor improvesoverall efficiency in this way which is an important object of thepresent invention.

A preferred embodiment of the present'invention is disclosed herein andcomprises a commercially available fly ball governor having a spring,opposing outward movement of the fly balls, the load of which may bevaried to two predetermined values by a solenoid which is energize'd inaccordance with the pressure within the intake manifold (hereinafterreferred to as manifold pressure) of the engine being governed. Sincethe spring has two o-peratingloads, the fiy balls have to develop twodi'iferent'values of centrifugal force to overcome the spring anddecrease the throttle setting of the carburetor or other charge-formingdevice of the engine. In this way the engine is governed at twodifferent operating speeds each of which is maintained whenever theengine intake manifold pressure is above or below predetermined valuesIt is also an object of the present invention to provide a governormechanism whichacts to increase the governed speed of an associatedengine whenever theload imposed on the engine and the resulting governoraction cause the manifold pressure to rise above a predetermined value.

Another object of the present invention is to provide a governormechanism which will automatically reduce the speed of operation of anassociated engine to the idling condition when the load on the engine isreduced or removed.

A still further object of the present invention is to provide a governormechanism which is responsive in its operation to the intake manifoldpressure of an associated internal combustion engme.

Another object of the present invention is to provide a governor forcontrolling a carburetor throttle valve which is in series with anotherhand operated throttle valve located between the carburetor and intakemanifold of the engine.

The novel features that are considered characteristic of the inventionare set forth inthe appended claims. The invention itself, however, bothas to its organization and method of operation, together with additionalobjects and advantages thereof, will best be understood from thefollowing description of a specific embodiment when read in conjunctionwith the accompanying drawing which shows diagrammatically the governormechanism associated with the carburetor and a portion of the intake orinduction manifold of the engine beinggoverned. Part of the governormechanism is shown broken away and in section to facilitate thedescription of its operation.

The'present invention comprises a commercially available fly ballgovernor, generally designated l, which is driven directly by thegoverned engine (not shown) through a gear 2. The governor acts tocontrol the positionof a throttle valve 3of a carburetor I; connectedtoand supplying a combustible mixture to an intake manifold 5 of aninternal combustion engine. This engine may be used to drive any powerconsuming device, mechanical electrical; and may be used to particularadvantage in drivihg D. C. and A. C. electric generators. v

A pressure switch, generally designate-d6, is in Communication withintake manifold 5 and controls the energization of a solenoid l whichwhen energized moves a bell crank 8 of the fly ball governor to a raisedposition, indicated in phantom lines at 9. The pressure switch mayincorporate a bellows l3 the interior of which is in communication withthe engine intake manifold through interconnecting pipe line I I. Whenthe pressure within the bellows exceeds a predetermined value, thebellows expands and closes an electric switch I2 which completes anelectric circuit I3 and energizes solenoid 1 with current drawn frombattery l4.

The fly ball governor itself may be any standard commercially availableunit modified as needed to meet the requirements of the presentinvention. A typical governor of this type is manufactured by the PierceGovernor Company of Anderson, Indiana. Such a governor incorporates ayoke l5 secured for conjoint rotation to shaft is to which gear 2 issecured. The yoke carries a pair of pivotally attached fly balls I!which, during rotation of shaft I6, tend to diverge from its center lineunder the influence of centrifugal force in a manner well known in theart. The fly balls act on a thrust collar (not shown) which imparts arotary movement to an Operating lever 18 and shaft is to which it isattached.

Throttle control arm 23 is secured to shaft [9 and may swing between thefull and phantom line positions shown. A connecting link 2| transfersthe motion of this arm to the throttle valve 3 which is held in arelatively open position when arm 20 is in its full line position and isheld in a relatively closed position when the arm is in the positionindicated by phantom lines.

A tension spring 22 is stretched between arm 20 and an adjustablemounting eye 23 which is threadedly secured to one arm of bell crank 8.Fly balls I! must overcome the tension of spring 22 before clockwiserotation can be imparted to shaft [9, which rotation results in closingthrottle valve 3.

Bell crank 8 has an outstanding arm which is connected by link 24 toaxially movable plunger 25 of solenoid T. Plunger 25 is moved from itsfull line to its phantom line position whenever solenoid I is energizedby the closure of electric switch 12. The movement of the solenoidplunger imparts rotation to bell crank 8 about its pivot pin 26 andstretches spring 22. As will be described more fully hereinafter, thephantom line position of the plunger prevails whenever the engine beinggoverned is subjected to a load. It is therefore to be noted that, whenthe engine is operated under load, spring 22 is in a relativelystretched position in comparison to a less stretched or tensionedposition prevailing during periods when the engine is idling and notcarrying any substantial load.

A second throttle value 21 is in serious with throttle valve 3 and iscontrolled by an extensible flexible cable 28 which may be movedmanually to adjust throttle valve 21 during periods when the engine isbeing initially started. When the engine is at rest, solenoid 1 will notbe energized, fly balls I! will be at rest and throttle valve 3 will beheld in an open position under the influence of spring 22 acting on arm20. When the engine is to be started, an operator manually opensthrottle valve 21 slightly and starts the engine in a conventionalfashion. Since valve 21 is in a relatively closed lit 4 position, theengine cannot gain speed sufii ciently for the fly balls I! to overcomethe tension of spring 22 and as a result valve 3 re mains in a full openposition.

When the engine has been warmed up and is to be placed under governorcontrol, the operator opens valve 21 fully. As this valve is opened, theengine rapidly ains speed and the fly balls overcome the tension ofspring 22 and rotate lever 20 in a clockwise direction to close valve 3.Spring 22 has a predetermined tension which can be overcome when the flyballs attain a relatively low rotational speed, such as 1300 R. P. M.,which for most engines is a rather fast idlin speed. If for any reasonthe engine should tend to exceed 1300 R. P. M., the fly balls impartadditional rotation to shaft I9 and close valve 3 until a newequilibrium condition prevails slightly above 1300 R. P. M. Conversely,should the speed tend to fall off for any reason, spring 22 willovercome the centrifugal force of the fly balls and open valve 3 tore-establish the idling speed of the engine.

During the idling period, the charge supplied to the engine is severelythrottled by valve 3 with the result that a very small absolutepressure, or in other words a sizable vacuum, exists in manifold 5. Thisis a natural operating condition for an unsupercharged engine.

By virtue of interconnecting pipe line H, bellows I0 of pressure switch6 is likewise subjected to a relatively large vacuum with the resultthat the bellows is collapsed allowing electric switch l2 to remain inits open position. Thus, the engine will continue to idle at 1300 R. P.M. under the conditions just described until a load is imposed on itsoutput shaft.

The immediate response of the engine to the imposition of a load is adecrease in its rotational speed. As its speed decreases, thecentrifugal force of the fly balls also decreases with the result thatspring 22 acts to move shaft I9 counterclockwise thereby opening valve3. The combination of a relatively wide open throttle valve and a lowengine speed permits the manifold pressure to rise rapidly towardsatmospheric pressure. As a result bellows I0 expands until electricswitch [2 is closed completing the circuit l3 and energizing solenoid I.Plunger 25 is moved to its upper position shiftng bell crank 8 toposition 9 and simultaneously increasing the tension load of spring 22on arm 20 to a higher predetermined value. The increased spring load onarm 20 immediately opens valve 3 to its fullest extent with the resultthat the engine, having a wide open throttle, rapidly accelerates andthe fly balls gradually develop sufilcient centrifugal force to overcomethe increased tension of spring 22. However, this increased tension canonly be overcome at a much higher rotational speed of the fly balls,such as 2300 R. P. M., which is a typical full load operating speed foran internal combustion engine. When this speed has been attained, thefly balls,

overcoming spring 22, rotate shaft [9 clockwise and gradually closevalve 3, thus holding the engine speed to substantially 2300 R. P. M.and adjusting the valve as required to maintain the speed of the engineregardless of what load is imposed. As valve 3 is opened and closedwhile the engine is being held at a uniform speed, the pressure in theinduction system rises and falls. However, the pressure never fallswhile the engine is under load to a value sufficiently low to permitbellows ID to collapse and switch 12 to open.

When the load is removed from the engine, the engine rapidly tends tooverspe'ed and fly balls I! rapidly act to close valve 3. As the valvecontinues to close, the pressure Within the en'- gine induction systemrapidly falls until bellows l collapses and switch I2 is opened. Theresulting de-energization of the solenoid permits outward. movement ofplunger 25 and a decrease in the tension of spring 22. This decrease inspring force, combined with the excessive speed of the fly balls, actsimmediately to close valve 3 still further, thus throttling the engineuntil the speed again falls to 1300 R. P. M- at which speed the engineis maintained in anticipation of another application of load.

When the engine is to be shut off, valve 21 is manually shifted to theclosed or idling position. As this valve gradually closes, the engine isexcessively throttled, the speed drops oif, and the fly ball governorgradually acts to open valve 3 to its fullest extent at which conditionthe engine may be shut off.

If it is considered desirable, the engine may be shut off while it isheld in the idling condition by the governor rather than by the handoperated throttle valve 21.

From the foregoing description it will be apparent that a very simpletwo-speed governor has been provided and that this governor will holdthe speed of an internal combustion engine alternately and automaticallyto either idling or full load commensurate with the load on the engine.It will also be apparent to those skilled in the art that the operationof the governor is perfectly stable and that the only deviationencountered in the regulated speed is that which is normally incidentalto fly ballgovernors.

It has been found advisable to provide an operating differential forpressure switch 6' so that solenoid I is energized and de-energized atslightly different values of manifold pressure. By providing such anoperating differential the solenoid is prevented from erraticallyswitching the governor between high and low speed settings, such asmight otherwise occur during slight fluctuations from the operatingpressure of the switch.

Pressure switch 6 is a conventional commercially-available unit. Aswitch which lends itself readily to use in the subject invention ismade by Penn Controls, Inc., Goshen, Indiana, and is identified as theirtype 155BVO1 vacuum control. This switch is adjustable both with respectto its particular operating range and the differential between itsopening and closing pressure; however, these adjustments are notmaterial in the present invention and have not been illustrated in thedrawing which is merely a diagrammatic showing. For instance, it will benoted that electric switch l2 incorporates an actuating arm 29 which ispivotally interconnected with a spring loaded toggle 30, movement of theactuating arm resulting from a slotted interconnection 3| with bellowsl0. By virtue of the overcenter toggle and the lost motion of theslotted connection, the construction produces an operating differentialbetween the opening and closing pressures.

Such an operating differential is also important for those engineswherein the valve timing is such that the manifold pressure at a givenoutput at high speed is below the manifold pressure corresponding tothis same power output at low speed. For engines having this typecharacteristic, a small operating differential is required to preventthe governor mechanism from hunting between the high and low speedgovernor setting when the absolute manifold pressure nears that valuenecessary to actuate switch 6. g

The governor mechanism has been described hereinbefore with particularreference to operation at high speed under load and operation at a lowspeed while idling or under no load. Itis obviously possible that thissame governor can be used to regulate enginespeed between a high loadand a lower load condition. In other words the governor can maintain anengine speed such as 2200 R. P. M. for operation at powers over 25% ofthe rated power and can maintain a lower speed for operation below thispower output. Thus, it is possible by the use of the present governor tohold the engine speed at a relatively low value, for example 1300 R. P.M., and to maintain this speed until a preselected pressure level withinthe manifold, corresponding to a pr'e'de termined percentage of theavailablepower at this speed, is attained. When this preselected valueisattained, the solenoid is energized and the engine throttle is adjustedfor the same power output but at a higher governed speed. Increasedloading of the engine beyond this point causes a; further increase ofmanifold pressure. Thus, the engine continues its operation at thehigher speed and solenoid 1 remains energized.

As the load is gradually removed from the engine the manifold pressuredrops to another predetermined value, below the first predeterminedvalue by the amount of the operating differential, at which solenoid 1is deenergized and the governor acts to reduce the engine speed to alower value as has been explained.

It has been found desirable to use' an operating difife'rential of atleast 3%; inches of mercury for pressure switch 6 to prevent the twospeed mechanism of the governor from hunting between the high and lowspeed settings under'all conditions of operation. For instance switch 6usually energizes solenoid 1 at an absolute manifold pressure of 17inches of mercury and de-energizes the solenoid at an absolute manifoldpressure of 12.5 inches of mercury.

Having described a preferred embodiment of my invention, I claim:

1. In a governor mechanism for an internal combustion engine having aninduction manifold, a governor having revoluble fly balls and a springopposing the centrifugal action of said fly balls, a solenoid theposition of which controls the total load of said spring, and a pressureswitch responsive to the induction manifold pressure of the engine, saidswitch energizing said solenoid to change the load of said spring whenthe pressurewithin the induction manifold of the engine rises above apredetermined value.

2. In a governor mechanism for controlling an internal combustion enginehaving an induction system which is supplied with a combustible mixtureby a carburetor, a governor, a carburetor throttle valve controlled bysaid governor, a spring opposing the action of said governor whileclosing said throttle valve, a solenoid for increasing the load of saidspring when energized, and means in communication with the engineinduction manifold for energizing said solenoid when the manifoldpressure attains a predetermined value.

3. A governor mechanism for an internal combustion engine having acarburetor connected to an induction system comprising a governor, a

throttle valve in the carburetor which is adjusted by said governor toregulate the engine speed, a spring the force of which acts at all timesto Open said throttle valve, means in communication with the inductionmanifold of the engine, said means having a movable member which isshifted to predetermined positions corresponding to predeterminedpressures within the manifold, said member biasing said spring wherebythe governed speed established by said governor is changed in responseto manifold pressure.

4. A governor mechanism for an internal combustion engine having anintake manifold and a charge forming device comprising a centrifugalgovernor driven by the engine, said governor adjusting the setting ofthe charge forming device to govern the speed of the engine, resilientmeans modifying the action of the governor in its adjustment of thecharge forming device, a solenoid having a movable member which biasessaid resilient means in the course of its movement, and pressuresensitive means in communication with the intake manifold, said pressuresensitive means energizing said solenoid when the pressure within themanifold rises above a predetermined value.

5'. A two-speed governor mechanism for use in conjunction with aninternal combustion engine having an intake manifold and a chargeforming device comprising a governor driven by the engine for adjustingthe charge forming device to regulate the engine speed, resilient meansagainst which the governor acts in governing the engine speed, asolenoid for biasing said resilient means when energized, and a pressuresensitive element in communication with the engine intake manihaving anintake manifold and a charge-forming device comprising a centrifugalgovernor driven by the engine for adjusting the setting of thecharge-forming device to regulate the engine power and speed, a springagainst which the governor acts in governing the engine speed, asolenoid for biasing said spring when energized and a pressure sensitiveelement in communication with the engine intake manifold, said elementcomprising an electrical switch and pressure sensitive means for openingand closing said switch in response to predetermined manifold pressures,the pressure at which said switch is closed bein above the pressure atwhich it is opened, closing of said switch energizing said solenoidwhereby said spring is biased and the governed speed of said engine isshifted to a higher value from that maintained by the governor when thesolenoid is de-energized.

7. A governor mechanism for an internal combustion engine having acharge-forming means connected to an induction system comprising agovernor, a throttle valve in the charge-forming means adjusted by saidgovernor to regulate engine speed, resilient means against which saidgovernor acts, and means in communication with the induction manifold ofthe engine, said means having a movable member which is shifted topredetermined positions corresponding to predetermined pressures withinthe manifold, said member biasing said resilient means whereby thegoverned speed established by said governor is changed in response tothe manifold pressure.

AUGUST W. RICKENBACH.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,047,702 Pfeil July 14, 19362,204,492 Heintz June 11, 94

